E-commerce has created significant opportunities for the corporations to understand the customers' expectations, desired values, to increase their satisfaction and to expand their market share, more efficiently. The most significant activity of e-commerce is in the field of e-banking and financial services. Customer satisfaction index is a concept introduced for evaluating of the service quality in electronic banking. Considering the relative importance of customer satisfaction in e-banking, defining scientific criteria for the assessment of mentioned index is very important. So, a scientific and efficient method is always needed. The purpose of this paper is to use the fuzzy data envelopment analysis (DEA) techniques for evaluating and ranking the efficiency of online customer satisfaction index in eight economic banks in Iran. Here, we first study the fuzzy set theory and the method of traditional DEA in the same model. Next, the relationship between them were developed, which provide the fuzzy DEA model with qualitative data. The SPSS and GAMS software package were employed to analyze the data collected through questionnaires. The results show that three economic banks in terms of customer satisfaction in e-banking were located on the efficiency border and were quite efficient.